Slug for condenser tubes



Jan. 26, 1932.

w. F. OBERHUBER' 1,842,563

SLUG FOR CONDENSER TUBES Filed Jan. 4, 1927 2 Sheets-Sheet l l 1/ I lJan. 26, 1932. w. F. OBERHUBER 1,842,563 v SLUG FOR CONDENSER TUBESFiled Jan.'4. 1927 2 Sheets-Sheet 2 Patented Jan. 25, 1932 PATENT OFF?"WILLIAM F. OBERHUBER, OF LANSDOWNE, PENNSYLVANIA, ASS IG-NOR T FRANKLINDEVELOPHEELNT COMPANY, OF PHILADELPHIA, PENNSYLVANIA, A CORPORATION OFPENNSYLVANIA Application filed January 4, 1927.

invention relates to longitudinally perfora l slugs for cleaningcondenser tubes and the like, and that operate by being driven wugh thedirty tubes by the pressure of l ich a fluid as air, steam or water.

it purpose of my invention is to simultaneously rotate and fmwvardlyprogress a rubber plug or slug through a condenser tube in; means of thedrii'in fluid, using the fluid pressure back of the i to drive itforward and the i'iuid passing through the slug to 1'0- te lo the singas well as to Wash away loosened dirt from ahead of the slug.

it further purpo:-:e is to enlarge the rear end of a rubber slug andprovide a flared opening therein to cooperate with longitudinallyextending external guides which maintain the slug in alignment and formclearance spaces between them to receive dislodged dirt.

further purpose is to removably mount 'ing at the rear of a slug,anchoring the spring! to the forward end of the slug, using 'priug ornot according to the condition e corulenser tube to be cleaned. it Afurther purpose is to guide the driving fluid to the surface of a slugat the front oi the slug by means of circumferentially extendinginterior grooves which flare to or nearly to the full diameter of theslug.

L ier purpose to use a hollow rubber slug a scraper spring behind it andto determine the tightness of the spring against the bore of the tube bythe force re- "u to pull the spring.

5 is fi'uther purpose .is to use spirally eX- tending interior fluidpassages in the slug, both for the purpose of guiding a dischargeagainst the tube in ad nurse of the slugs and to pass anchors for atrailing scraper carried by the slug.

further purpose is to trz'insform longitudinally extending guide ribsupon a slug eX- terior into ircuuiferoutially moving scrapiuosu r to b vthe reaction of operating fluid pa nun through the slug along spiralpaths.

have preferred to illustrate a few slightly different slugs only, all ofone general form, aiming the many in which my invention may appear.selecting slugs which are practical, efficient, reliable and inexpensiveand which SLUG FOR CONDENSER TUBES Serial No. 158,879.

at the same time Well illustrate the principles of my invention.

Figure 1 is a side elevation of one of the slugs, corresponding to theview from the position of line 11 in Figure 2.

Figure 2 is a rear end elevation of the structure seen in Figure 1.

Figure 3 is a front end elevation of the structure seen in Figure 1corresponding to the View from line 3-3 of that figure.

Figure i is a section taken upon the line 4il of Figure 5.

Figure eta is a section slightly modified from Figure Figure I is asection corresponding to line 55 of l igure 4.

Figure 6 is a fragmentary longitudinal view of a tube section and of oneof my slugs in place to which I have added a spring scraper, the viewcorresponding to line 66 of Figure '2' but being slightly modifiedtherefrom.

Figure 7 is a section upon line 7--7 of Figure 6.

Figure 8 is a side elevation of a second slug facing in the oppositedirection from Figure 1.

Figure 9 is a front elevation of the structure seen in Figure 8.

Figure 10 is a section of Figure 9 taken upon line 10-10.

Figure 11 is a rear elevation of the structure seen in Figure 8.

Figures 12 and 14- are front and rear elevations respectively of aslightly changed slug.

Figure 13 is a section of Figure 12 upon line 1313.

Figure 15 is a longitudinal section of a structure corresponding toFigure 10 but with a scraper in position.

Figure 16 is a rear end elevation of the structure seen in Figure 15.

In the drawings similar numerals indicate like parts.

This invention is in part a development of the subject matter of myapplication, Ser. No. 85,533, filed February 2, 1926.

In the above application I disclosed and claimed an internally rifledslug in order to make it rot-ate during its passage through a condensertube by the reaction of the driving fluid. I did not at the time of theprior invention appreciate the advantage of rifling or internallyspiralling throughout the full length of the slug and particularlythroughout the discharge end of the perforation. I also did notappreciate the advantage of providing simultaneous clearance and guidingsurface in front of the Wiping portion of the slug.

Describing this form shown in Figures 1-5:

The slug is made of rubber and comprises externally a forwardlyextending ribbed guiding portion having ribs 20 and intervening grooves21 with a cylindrical enlarged sealing flange 22.

The slug is hollow and is grooved so as to provide spiral passages 23which are farther apart at the front and at the rear than at the middle.The enlarged opening provided by the enlargement of these passages atthe rear at 24 facilitates nearly radial compression of this rear flange22 so that the slug may pass through a tube 25 (Figure 6) somewhatsmaller than the diameter of the flange 22. At the same time thisinwardly compressible flange becomes radially expansible by the pressureof the driving fluid so that the fit of the flange against the tube is afunction both of the expansive power of the rubber and of the pressureand character of fluid by which the slug is being driven.

The spiral passages are not only further from the center at the frontand rear than at the middle, but are larger in cross-section, consideredmerely as passages, also at these two ends providing a convergence andwith a compressible fluid a compression of fluid from the rear to themiddle with a corresponding divergence and expansion (with an expansiblefluid) of the fluid streams beyond the middle to their point ofdischarge near the circumference. The discharging streams leave the slugnear the circumference with a. direction which is spiral and which isalso divergent from the axis, with the result that they strike theinterior of any tube 25 in a direction which is diagonal and a compositeof these two slopes and which is highly desirable for the purpose ofcutting the dirt ahead of the advancing slug.

Ordinarily these slugs are driven by water, steam or air. Where water isused there is no bodily compression nor expansion of the stream, butwith steam and air there will be compression from the rear to apredetermined point shown near the middle and expansion beyond thispoint. with either water or steam the fluid will have the effect ofwetting the layer of dirt within the tube and thus facilitating itsremoval.

The construction and location of the spiral passages provides an openinterior within the grooves to passages at the front and a plug tendedto tbe shown in Figure 4. In it the forward flares of the passages intheir entireties as well as of the sections of each indiif idual passageextend clear to the front surace.

The expansion of the individual passages toward the forward end maydesirably be omitted where the guiding. fluid is a liquid. Vfhere thetube is used sometimes with air or steam and sometimes with water Iprefer to have the forward end of the passages through the slug expand.

In the form shown in Figures 6 and 7 the slug is desirably the same asin Figures 1 to 5.

When a condenser tube is very dirty, particularly when hard scale isdeposited upon the inside of the tube, the rubber material of the slugis inadequate to remove the scale. I then fasten a spiral spring 27 tothe slug. The forward spiral of the spring slug is of reduced size andsurrounds the head of a fastening member 28 which extends through theslug and is anchored at the forward end thereof. Preferably thefastening member is provided with a head 29 and two stems 30 which passthrough two of the slug passages and registering passages 31 of a washer32. They are then bent over the washer at 32, thus securing andanchoring the spring.

lVhen the slug is driven through a tube and the spring is in place theslug pulls the spring along and the pull is carried upon the washerthrough the divided stem of the fastening member. The spring tends tounwind with the strain upon it, reducing its diameter in proportion tothe resistance met, i. e., according to the volume and hardness of thescale.

The spring and washer are very readily removable by turning up the endsof the stem members. However, ordinarily, a small number of slugs withsprings will be kept for this service. Unless the tube to be cleaned isin bad condition the spring will usually not be needed. 7 When drivingthe slug through a condenser tube without its auxiliary spring, I preferto use air or steam as a driving medium but find it preferable to usewater when the spring is used.

In operation the space 21 between the external guiding ribs 20 providesa region for receiving dirt wiped from the inside of the tubes. Theblast of driving fluid is discharged forwardly and circumferentiallynear the forward edge of the slug and drives much of the dirt ahead andout of the way. Usually a slug will be sent through a number of timesbefore a tube is cleaned. If the tube be very dirty initially the springmember shown in Figures 6 and T will preferably be used at first to takeout the rough heavy scale. Subscquently the slug may be sent through a number of times without the spring for final cleaning and polishing.

It find that T can clear the dirt in large measure from the grooves 21by either of two methods through the use of openings from these channelsinto the adjacent passages 23. i prefer to use these openings forsuction of the dirt and scale through them into the nozzle channelsreferred to as passages 23 and when so used place the openings near orbeyond the middle of the length of the grooves, preferably at the pointsof greatest restriction of the passages where the velocity of the luiiiiis accordingly greatest. The openings are so shown in Figure l and arethere rai'lially. lowever they can be sloped laterally or in planesthrough the axis or as a combination of these.

The holes 3-1- are shown in Figures 1, 1 and in only and no holes areshown in Fig are (3. it will be obvious that they could be used in anyof the structures shown. They n enter the channels 23 at any point Wherere will be an injector effect and their ternnnation at the points ofgreatest passage ronz-iitriction has been determined upon for thepurpose of getting the highest fluid velocity for suction and for thispurpose only.

I find that sucking of the dirt into the dream of driving fluid or gasthrough the openings 34 has an advantage additional to the clearing ofthe paces or grooves 21 in that the dirt thus fed into the drivingstream contains some scale and when driven by the stream has a sandblast effect upon the scale and dirt engaged by the stream in advance ofthe plug.

The other means of using these openings is by outward blast into thegrooves as distinguished from the suction means. I have shown it inconnection with Figures 8, 10 and ii. but not in 15. In Figures 8, 10and 11 the openings 36 connect with the interior toward the rear of thesing and open into the 'ear parts of the grooves 21 so that there is ablast of air through these rear openings and out through the grooves, asdistinguished from the suction present in the other form. lilvidentlythese blast openings shown in Figures a, 10 and 11 can be applied in anyof the figures.

lt is, of course, evident that the two means of clearing the grooves ofdirt and scale are capable of use together so that fluid pressureentering the grooves at the rear from opening; such as 36 will supplyfluid pressure in the grooves to assist in the inward flow of fluid,dirt and scale due to suction through the openings 34. As seen in thesection 4a these two sets of openings may be mechanically assisted byforming a slight pocket 37 extending transversely of each groove 21 sothat dirt and scale crowding in toward the front by reason of theforward movement of the slug will be trapped at this point and will moreconveniently and effectively be sucked down by the suction of theinducing fluid and forced down into the inducing fluid by the pressureof fluid passing through openings 86.

l: have omitted the openings 34 and 36 from some of the slugs, haveshown one set 3% or one set 30 only in others and both SQLS of openingsin Figure do for the purpose of indicating that these parts of myinvention may be used or not as preferred and where used, the suctionalone may be applied or the pressure alone, or both suction and pressureas preferred.

In Figures 8 to 16 the slug is solid except for separate openings 23and, where a spril'lg is to be used, a central hole 88 shown in Figures15 and 16. Four openings 23 are shown in each of Figures 811 and 15 and16 whereas asingle opening 23 only is shown in Figures 12--1il. Each ofthe openings 23 is spiraled and is flared from back to front. They donot diverge radially.

Though the split pin form of fastening the spring shown in Figures 6 and7 is preferred and could be used I have shown a bolt 39 fitting into afront washer l0 used as a nut,

just to indicate that other fastenings may beused. It may be burr-ed tolock the bolt from withdrawal.

It will be evident that air or steam may be expanded, diverged from theaxis and given a circumferential whirl at the same time by the shape andlocation of the fluid passages, or that any one or two of these featuresmay be used together where the entire combination is not desired.

The reaction of the fluid against the walls of the passage and of theejected fluid against the air and against the interior walls of the tuberesult in turning the slug while it is passing through the tube. Attheir forward ends the ribs are expanded against the tube interior bythe pressure of the fluid against the outer walls of the passages. litwill be noted that the passages preferably agree in number with thenumber of ribs and terminate directly beneath them.

The rotation of the slug causes the longitudinal edges of the guidingribs to assist in cleansing the interiors of the tubes, the dirt scrapedand rubbed off accumulating in the grooves between these guiding ribs.

In view of my invention and disclosure variations and modifications tomeet individual whim or particular need will doubtless become evident toothers skilled in the art, to obtain part or all of the benefits of myinvention without copying the structure shown, and I, therefore, claimall such in so far as they fall within the reasonable spirit and scopeof my invention.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent is 1. A slug for cleaning condenser tubes,comprising a hollow rubber body, a rear sealing flange and externalforward guiding ribs, the body having an interior spiralled groovereduced in cross-section from the rear to approximately the middle andenlarged forwardly thereof.

2. A slug for cleaning condenser tubes comprising a hollow rubber bodyhaving a plurality of interior fluid passages converging toward oneanother and reducing in distance from the axis from the rear to anintermediate point and diverging from one another and increasing indistance from the axis from that point to the front of the slug.

3. A slug for cleaning condenser tub-es, comprising a hollow rubber bodyhaving a plurality of interior fluid passages converging toward oneanother and reducing in distance from the axis from the rear to anintermediate point and diverging from one another and increasing indistance from the axis from that point to the front of the slug, andhaving a solid portion at the front between the fluid passages.

4. A slug having a rubber body, said body having spiralled passages fromrear to front diverging from the middle portion of the length of theslug.

5. "x slug having a rubber body, said body having spiralled passagesfrom rear to front converging from the rear for a portion of the lengthof the slug and then diverging to the front of'the slug.

6. A slug having a rubber body, said body having a centrally open hollowforwardly from the rearward end for a portion of the length of the slugand including a plurality of grooves about the open central portion ofthe hollow and having passages spiralling and diverging forwardly fromthe hollow to the front of the slug.

7. A slug having a rubber body, said body having a hollow forwardly fromthe rear ward end for a portion of the length of the slug and aplurality of grooves about the hollow communicating therewith andpassages spiralling, flaring and diverging from the forward end of thehollow to the front of the slug.

8. A rubber slug hollow forwardly for a portion of its length from itsrearward end, having forwardly converging spiralled grooves extendingforwardly from the rearward end of the hollow and connecting withspiralled passages from the hollow to the front of the slug and disposedabout the center line of the slug, the grooves and passages being largerin cross-section at the rear and front of the slug respectively than atintermediate points of the slug.

9. A. rubber slug hollow for a portion of its length from its rearwardend, having forwardly spiralled grooves about the hollow and passagesconnected therewith spiralling to the front of the slug and disposedabout the center line thereof at the front, the grooves and passagesbeing larger in crosssection at the rear and front respectively than atintermediate points of the slug, respectively forwardly convergingtoward the axis and diverging from the axis.

10. In a slug for cleaning condenser tubes, a rubber body, guiding ribsexteriorly of the body extending longitudinally over the middle of thelength and to the front portion of the body, and a rear flange largerthan the ribs and adapted to be swelled by the driving fluid, the rearend of the body being hollow within the flange.

11. A slug of rubber having a plurality of external longitudinallyextending guiding ribs and corresponding passages through the bodyterminating beneath the ribs.

12. A slug of rubber having its front end formed with alternating ribsand grooves and having forwardly flaring passages through the slugterminating respectively beneath the ribs. I

13. In a slug for cleaning condenser tubes, a rubber body, a scraperadapted to be dragged by the body, a pressure-distributing plate acrossthe front of the slug, and a fastener for the scraper passing throughthe body and anchored in the plate.

M. In a slug for cleaning condenser tubes, a rubber body having passagesthrough it diverging from the axis toward the forward end and externallongitudinal ribs on the forward part of the body forming groovesbetween them, there being openings from the grooves to the passagesproviding suction from the grooves into the passages by ejector effect.

15. In a slug for cleaning condenser tubes, a hollow rubber body,longitudinally extending ribs on the forward part of the body forminggrooves between them, and blast openings from the rear part of thehollow body into the grooves.

16. In a slug for cleaning condenser tubes, a hollow rubber body, a rearflange: on the body and longitudinally extending ribs on the bodyforming grooves between, there being blast openings toward the rear intothe grooves and suction openings ahead of the blast openings, extendingfrom the grooves to the hollow of the body.

WILLIAM F. OBERHUBER.

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